Description: On January 24, 1925, for the first time in over a century, a total solar eclipse would be visible across the northern part of the United States. How scientists used a dirigible to observe the phenomenon.
Description: [caption id="" align="aligncenter" width="360" caption="Steven Cohn, the Smithsonian’s Office of Safety, Health and Environmental Management and the museum’s representative Industrial Hygienist, tests Owney's fur for arsenic, lead and mercury. Courtesy of the National Postal Museum "Pushing the Envelope" blog."][/caption] More interesting preservation challenges. We’ve covered